On Wed, Feb 27, 2013 at 09:39:47AM -0800, Joe Perches wrote: > On Wed, 2013-02-27 at 12:16 -0500, Nicolas Pitre wrote: > > On Wed, 27 Feb 2013, Joe Perches wrote: > > > On Wed, 2013-02-27 at 16:31 +0000, Russell King - ARM Linux wrote: > > > > On Wed, Feb 27, 2013 at 07:49:12AM -0800, Joe Perches wrote: > > > > > On Wed, 2013-02-27 at 09:56 +0000, Russell King - ARM Linux wrote: > > > > > > On Tue, Feb 26, 2013 at 05:40:34PM -0800, Joe Perches wrote: > > > > > > > On Tue, 2013-02-26 at 22:10 +0000, Russell King - ARM Linux wrote: > > > > > > > > So... for a selected kernel version of a particular size, can we please > > > > > > > > have a comparison between the new LZO code and this LZ4 code, so that > > > > > > > > we can see whether it's worth updating the LZO code or replacing the > > > > > > > > LZO code with LZ4? > > > > > > > > > > > > > > How could it be questionable that it's worth updating the LZO code? > > > > > > > > > > > > Please read the comments against the previous posting of these patches > > > > > > where I first stated this argument - and with agreement from those > > > > > > following the thread. The thread started on 26 Jan 2013. Thanks. > > > > > > > > > > https://lkml.org/lkml/2013/1/29/145 > > > > > > > > > > I did not and do not see significant value in > > > > > adding LZ4 given Markus' LZO improvements. > > > > > > > > Sorry, a 66% increase in decompression speed over the updated LZO code > > > > isn't "significant value" ? > > > > > > We disagree. > > > > > > > I'm curious - what in your mind qualifies "significant value" ? > > > > > > faster boot time. smaller, faster overall code. > > > > Sorry, but you certainly successfully got me confused, and probably > > others as well. > > > > RMK says that "66% increase in decompression speed over LZO" is > > significant. You apparently disagree with that. > > Yeah, I can see how that can be interpreted. > I'm referring only to the new LZO. > > I guess Russell has not reviewed the new LZO. > > There is apparently no speed increase for LZ4 over > the new LZO. Total claptrap. I've no idea where you're getting your data from, but it's franky wrong and you're now being totally misleading to anyone else reading this thread. I explicitly asked for a comparison of the _new_ LZO vs the LZ4 code, and this is what I received from Kyungsik Lee in this thread: Compiler: Linaro ARM gcc 4.6.2 2. ARMv7, 1.7GHz based board Kernel: linux 3.7 Uncompressed Kernel Size: 14MB Compressed Size Decompression Speed LZO 6.0MB 34.1MB/s Old ---------------------------------------- 6.0MB 34.7MB/s New 6.0MB 52.2MB/s(UA) ============================================= LZ4 6.5MB 86.7MB/s UA: Unaligned memory Access support And my statement of a "66% increase in speed" of LZ4 is comparing the _new_ LZO code with unaligned access with the LZ4 code. Now, you refer to Markus' results - but Markus' results do not say what they're comparing - they don't say what the size of the compressed image is, nor what the size of the uncompressed image was. Now, Markus' results show a 42% increase in speed between the LZO-2012 and LZO-2013-UA versions (do the calculation yourself - I'm sure you're capable of that? If not, we can turn this into a maths lesson too). The above shows a 53% increase in speed between the existing LZO code and the new LZO code with unaligned accesses. _But_ the above shows an additional 66% increase between the new LZO code with unaligned accesses and LZ4. Or, a whopping 150% increase in speed over the _existing_ LZO code. So please, stop stating what I have and have not reviewed. Unlike you, I _have_ been following everything that's been said in this thread, and - unlike you - I have analysed the figures put forward and drawn conclusions which are fully supported by the published data from them, and stated them - now many times. -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
